A blind friend of mine was stopped at security at EWR because his shoes set off the detector. He had his cane with him and was quite clearly blind.
Quite rightly security ran him through extra checks which while they only took a couple of minutes left him quite distrought. At no time did they explain to him what they were doing, they most definately did treat him like a criminal and at the end of the procedure left him without telling him they were done. He couldn't even find his shoes because they didn't tell him where they had taken them - they were sitting on the x-ray machine belt!